“I've said many times before that it is not possible to debate the balance between privacy and security, including the rights and wrongs of intrusive powers and the oversight arrangements that govern them without also considering the threats that we face as a country," she told MPs.

"Those threats remain considerable and they are evolving.

"They include not just terrorism from overseas and home-grown in the UK, but also industrial, military and state espionage.

"They include not just organised criminality, but also the proliferation of once physical crimes online, such as child sexual exploitation. And the technological challenges that that brings.

"In the face of such threats we have a duty to ensure that the agencies whose job it is to keep us safe have the powers they need to do the job."

David Davis MP told The Times there is "no proven need" to retain the data for a year.

Previous plans to introduce the measure in the so-called snooper's charter in 2013 were blocked by the Liberal Democrats in the Coalition.